Thermo Fan Switch

[RUN415]

Hi All,

I was driving over heavy corrugations and the air con 'popped'.
(eg: Sudden short hiss - I soon discovered it spat out coolant from the somewhat corroded accumulator thing at the front of the radiator.)

Not sure if it's related but a short while after that I noticed that the
thermo fan wasn't coming on when I turned on the air con...as it used to.

I bridged out the LO FAN relay and the thermo fan came on...so it's still working ok.

SO my question is:
Is there any disadvantage (besides making the fan completely manual)
to just bridging out the relay socket with a (in cabin) switch???

For me it just seems easier (no splicing into wires etc) and I know it's going to work...
...as I must consider there is now another (air con?) fault somewhere?

Cheers.

 

[losh1971]

You have lost all the gas. You need to have the broken pipes replaced as they corrode over time and break. Condensor might also be broken but won't know until the pipes are removed. Condensors wear out on the pipe joins. The threads strip and break.

 

[deserthead]

As Losh said, you've lost all your refrigerant from your AC system.

The reason the fan is not coming on when you have the AC on is the pressure switch is no longer engaging (ie - No pressure), which in turn will not call for the fan to turn on. Perfectly normal.

If you want to test that your fan will still operate as per the BCm, disconnect your coolant sensor. Fan should kick in low speed, then after half a min or so, it will ramp up to high speed.

Once you get your AC fixed, it will operate as normal again.

 

[losh1971]

If you decide to fix the air get the condensor and pipe work all apart and checked before the tech orders parts. My broken pipe started out as a $200 repair but escalated into around 700 as he kept finding more problems as he delved deeper, after he ordered some initial parts.

 

[jeepster]

lookup a thread in general forum
"Hard wired Thermo ecu by pass"

 

[RUN415]

Thanks for the replies...appreciate it.

That stuff about the pressure switch is interesting - good to know...
...at least I understand what's goin' on with the fan + air con now.
Makes perfect sense.

Thanks LOSH - I don't think I'll be fixing the air con any time soon.

As no one said it's a bad idea to run the switch thru the relay socket
...I think I will proceed with that plan.
I'm the only one that drives the car (once a week) and most of that is highway...
...so having the fan on 'manual' is no drama at all - it's just for occasional use.

The (PCM / BCM?) thermo fan control is next to useless anyway...it's always been way too late...
...you can 'smell' the engine starting to cook before it kicks in - it's awful.

Cheers.

PS> Here's the 'HARD WIRED THERMO' link 'jeepster' suggested...
https://forums.justcommodores.com.au/threads/hard-wired-thermo-ecu-by-pass.270346/
It's about thermal switches...which sound pretty handy.